Wet Cup Research Articles

Water Vapour Resistance of Exterior Coatings—Influence on Moisture Conditions in Ventilated Wooden Claddings

Increasing climate fluctuations and extremes due to climate change are particularly concerning for wooden building envelopes, especially in the Nordic region, which has harsh climatic conditions. The exterior coating’s barrier properties are crucial for maintaining building envelopes’ intended lifespans. Hence, it is unfortunate that the vapor resistance of exterior coatings is not openly accessed for commercial products. This study investigates the influence of the water vapour resistance of exterior coatings on the moisture conditions and mould growth risk of ventilated wooden claddings. The sd-value (vapour diffusion-equivalent air layer thickness) is determined for nine free-standing coatings (alkyds, emulsions, and acrylics); in total, 100 specimens are tested with the wet cup method. Additionally, with WUFI Pro, one-dimensional hygrothermal simulations under Nordic climatic conditions investigate how the coatings’ vapour resistance might influence the moisture dynamics of wood. The mould risk is assessed by the add-on WUFI VTT Model. The determined sd-values for the coatings range from 0.453 to 1.350 m (three layers) and from 0.690 to 2.250 m (six layers), showing a strong correlation with the dry film thickness. The vapour resistance of the coatings does not significantly influence the wood moisture content, but lower resistance may cause slightly faster drying. The importance of surface treatment is confirmed. The mould risk is notably higher in a Stavanger climate on a southwest-facing wall compared to Trondheim on a north-facing wall.

Hook Fabric Electroencephalography Electrode for Brain Activity Measurement without Shaving the Head.

In this research, novel electroencephalogram (EEG) electrodes were developed to detect high-quality EEG signals without the requirement of conductive gels, skin treatments, or head shaving. These electrodes were created using electrically conductive hook fabric with a resistance of 1 Ω/sq. The pointed hooks of the conductive fabric establish direct contact with the skin and can penetrate through hair. To ensure excellent contact between the hook fabric electrode and the scalp, a knitted-net EEG bridge cap with a bridging effect was employed. The results showed that the hook fabric electrode exhibited lower skin-to-electrode impedance compared to the dry Ag/AgCl comb electrode. Additionally, it collected high-quality signals on par with the standard wet gold cups and commercial dry Ag/AgCl comb electrodes. Moreover, the hook fabric electrode displayed a higher signal-to-noise ratio (33.6 dB) with a 4.2% advantage over the standard wet gold cup electrode. This innovative electrode design eliminates the need for conductive gel and head shaving, offering enhanced flexibility and lightweight characteristics, making it ideal for integration into textile structures and facilitating convenient long-term monitoring.

Hygric properties of porous building materials (VIII): Influence of reduced air pressure

Hygrothermal properties of porous building materials are indispensable for understanding and optimizing the hygrothermal performance of building enclosures and the built environment. In high-altitude areas, the influence of reduced air pressure on hygrothermal properties should be considered and, if needed, proper corrections should be adopted. Currently, the impact of reduced air pressure on thermal properties has been thoroughly investigated while that on hygric properties remains unclear. In this research, hygric properties of three representative porous building materials – calcium silicate, autoclaved aerated concrete and ceramic brick – are measured at three different air pressures, namely 1.00, 0.80 and 0.60 atm. The static gravimetric test, psychrometer test, cup test and capillary absorption test are performed to obtain the sorption isotherm, moisture retention curve, vapor permeability, capillary absorption coefficient and capillary moisture content. Results show that the influences of air pressure on the sorption isotherm, moisture retention curve, capillary absorption coefficient and capillary moisture content are limited, while the vapor permeability increases obviously with the decreasing air pressure. Specifically, the vapor diffusion resistance factor remains stable in the dry cup test, and this can be predicted by Schirmer's law. In the intermediate cup and wet cup tests, where liquid water contributes to the moisture transfer, the impact from air pressure becomes smaller.

Water vapor transmission parameters of the Kežmarok sandstone

Dynamic complex heat and water transport in building constructions can be calculated using modern simulation software such as Wufi, Delphin, Math, Comsol Multiphysics and other. This software is suitable for the evaluation of the thermal and hygric processes in constructions of historical buildings. Because it includes many important factors such as dynamic boundary conditions, solar radiation, driven rain, ground water, diffusion and others. The heat and water transport parameters of historical materials are needed for simulation of coupled heat and water transport in building materials. The Kežmarok sandstone was chosen for analysis. One of the important material parameters for evaluation of complex heat and water transport in building constructions are water vapor transmission parameters. Vapor transport can be described as water vapor diffusion resistance factor, water vapor diffusion coefficient and diffusion equivalent air layer thickness. The dry cup and wet cup method were used to determine the water vapor transmission parameters of Kežmarok sandstone.

Hygrothermal Modelling of the Differences between Single versus Variable Relative Humidity Vapour Diffusion Resistivity Properties of Pliable Membranes

The study investigates through hygrothermal modelling the effect of different boundary conditions and varying measured vapour diffusion resistivity values on the hygrothermal performance of five pliable membranes. Previously, this research quantified the variable water vapour diffusion resistivity properties of five different pliable building membranes. The membranes were assessed under varying humidity conditions using the gravimetric wet and dry cup test method. The varying humidity conditions better represent the boundary conditions experienced by materials in the building envelope. The pliable membranes include two permeable, two impermeable, and one variable products, which are commonly used to provide air and vapour control layers in the construction of framed external wall systems. This article focusses on the transient hygrothermal modelling of each of these membranes as a component of a typical timber-framed, clay brick veneer external wall system. The simulations were completed for three different climate types, namely, hot and humid, temperate, and cool-temperate with snow, and with a northern and western orientation. The results from hygrothermal and bio-hygrothermal simulations highlighted different responses subject to climate type and orientation. These results show that there are significant differences in simulated moisture and mould growth risk between the results of pliable membranes with single vapour resistance factor value and pliable membranes with multipoint vapour resistance factor values.

Water vapour transmission properties of uncoated and coated wood-based panels

ABSTRACT Knowing the properties of wood-based building materials is essential for their proper use. Moisture transfer properties of building materials are crucial to proper building design and the prevention of moisture-related problems. In selecting materials for the building, it is important to know their water vapour transmission properties. In this research the water vapour transmission properties of uncoated and coated particleboard, oriented strand board (OSB) and birch plywood were studied using wet cup method and a moisture gradient in the samples was additionally measured. The water vapour transmission rate of free films of three commercial transparent coatings was also studied. Results showed that particleboard had the highest water vapour permeability and that the coatings reduced the water vapour permeability of all tested wood-based panels. Moreover, sanding increased the water vapour permeability of uncoated particleboard and OSB. The moisture gradient in all tested wood-based panels was linear. The highest water vapour transmission rate was recorded for acrylic water-borne coating, followed by polyurethane water-borne coating and the lowest for polyurethane solvent-based coating.

Measurement of the water vapour permeability of earth plasters using small-scale wind tunnels under variable air flow regimes

To determine the water vapour permeability of porous building materials, the wet cup and dry cup tests are frequently performed. Those tests have shown to present high discrepancy. The water vapour permeability of building materials is an essential parameter to determine the hygrothermal behaviour of the material and its impact on indoor comfort. Several previous studies have aimed to improve the reproducibility of the tests, by improving the protocol, the analysis of the results, notably by taking into account the surface film resistance. Yet, it is commonly accepted with no evidence that this surface film resistance can be neglected for an air velocity above 2 m/s over the cup. This study aims at experimentally testing the influence of either the flow regime or the flow velocity on the robustness of the measured water vapour permeability. For this purpose, two mini wind tunnels were designed to produce a laminar or a turbulent flow above the cups with variable air velocity. Water vapour permeability tests were performed in the tunnels with varying air velocity and flow regime on earth plasters with different compositions. The results have shown that regardless of the air velocity and flow regime, the surface film resistance should not be neglected. Based on the presented results, to reach an optimal repeatability, the use of wind tunnels should be considered as they allow to precisely control the air flow above the samples.

Accuracy of water vapor permeability of building materials reassessed by measuring cup's inner relative humidity

Cup experiments are the most widely used method to measure the water vapor permeability of porous building materials. For this test, cup assembly is designed to create a vapor pressure gradient across a sample and, thus, to allow vapor diffusion through it. Water vapor permeability is assessed by weighing cup assembly over time. While the external conditions are generally well controlled, appropriate solid desiccants or saturated salt solutions are used to control the conditions inside the cup. However, precise knowledge of these conditions is crucial, as they are used to calculate permeance and hence water vapor permeability. In this study, dry and wet cup experiments were performed with different solid desiccants or saturated salt solutions on nine materials with Sd-values ranging from 0.08 m to more than 1 m. In all the experiments, the relative humidity within the air layer in the cup was measured with wireless sensors. The results showed that relative humidity was rarely the same as the expected value and that the relative humidity of solid desiccant also varied over time, resulting in from 5% to 450% relative errors in the predicted Sd-value. A correction method is proposed to assess the “real” Sd-value from the theoretical Sd-value and differences between dry and wet cup experiments are discussed.

Evaluation of the Protective Effect of The Cup Therapy on the Epileptic Seizure in Rats

Objective: Cup therapy has an important place in traditional and complementary medicine applications. The purpose of our study, this is the first time to investigate the protective effect of cup therapy in rats on experimentally generated epileptic seizures in new rat modeling created by different anatomic regions.
 Methods: In our study, 42 Wistar albino rats 3-4 months old (200-250 g) were used. Four other groups (n=7) except G3 and G4, 24 hours after cup therapy application, PTZ (35 mg/kg, sc., 0.2 cc) was injected, followed by behavioral epilepsy scoring.
 Results: In the 'Open Area' and 'Elevated Plus Maze' tests, there was no behavioral difference between the cup therapy group and the control group (p > 0.05). Given all the parameters, the G4 group significantly reduces the seizure compared to other groups (p < 0.05). There is a significant difference in G2, G5 and G6 groups compared to G3 in the phases parameter (p < 0.05).
 Conclusions: In this study, the new wet cup therapy (G2), which was applied for the first time, had a protective effect on seizures. G2, G5 and G6 groups are observed to suppress seizures compared to G3. Our findings are expected to contribute greatly to animal model analysis in the future.

Water vapor diffusion models in asphalt mortar considering adsorption and capillary condensation

Water vapor diffusion persistently and extensively existing in asphalt pavement is one of the important contributors to moisture-induced damage. Non-Fickian diffusion of water vapor in asphalt mortar has not been deeply understood due to the lack of quantitative characterization of water molecular transport in micropores affected by the adsorption and capillary condensation. The objective of this study is to establish diffusion models considering the effects of the adsorption and capillary condensation and quantitatively characterize the dependence of diffusion coefficient on the humidity and sample thickness. The diffusion characteristics of water vapor in asphalt mortar with various thicknesses under various humid conditions were investigated using a standard wet cup method. The results suggest that in the steady diffusion the measured mass loss of diffusive water vapor linearly increases with time. The apparent diffusion coefficients determined by the first Fick’s law demonstrate a nonlinear rapid reduction from 51.45×10–9 m2/s to 12.66×10–9 m2/s while the relative humidity varies from 22% to 95%. The diffusion coefficient nonlinearly decreases from 40.92×10–9 m2/s to 24.71×10–9 m2/s while the sample thickness increases from 3.62 mm to 16.34 mm. The molecular transports in gaseous flow, surface flow, and capillary condensate flow were introduced to formulate the effects of adsorption and capillary condensation. Combining the measured adsorption isotherm of water vapor in asphalt mortar, a diffusion model considering adsorption was derived and quantitatively characterizes the diffusion coefficients varying with the relative humidity. The dependence on relative humidity is attributed to the thickening of adsorbed water film in high humidity that changes the diffusivities in gaseous flow and surface flow. Another diffusion model considering capillary condensation was established to formulate the thickness-dependent diffusion coefficients in asphalt mortar. The dependence on the sample thickness is explained as the variable ratio of the diffusion in capillary condensate flow to the overall diffusion in a thick sample. This study provides a feasible approach to quantifying the environment-dependent diffusion characteristics and promotes the understanding of non-Fickian diffusion of water vapor in asphaltic materials.

Empirical Investigation of the Hygrothermal Diffusion Properties of Permeable Building Membranes Subjected to Variable Relative Humidity Condition

Hygrothermal modelling is increasingly used to inform building envelope design. A key input for these calculations is the material’s vapour diffusion properties. Respecting a growing international concern, this research has questioned the appropriateness of the current test method to establish construction material for vapour diffusion properties. This article reports on the empirical measurement of the vapour diffusion properties of two vapour-permeable building membranes commonly used in Australia residential systems when subjected to variable relative humidity conditions. The method involved completing dry cup and wet cup standard tests as specified in ISO 12572, (23 °C and 50% relative humidity RH). Further tests were then conducted as temperature remained at 23 °C but the relative humidity changed to 35%, 65% and 80%, respectively, in order to know if the diffusion properties are the same or change with varying relative humidity. The results from the wet cup and dry cup tests under different relative humidity conditions were non-linear and different. These results indicate vapour-permeable membranes behave differently when exposed to different relative humidity conditions. In conclusion, this research demonstrates that the current vapour resistivity test method is inadequate, hence the need to establish more detailed diffusion resistivity properties in different humidity ranges that represent conditions experienced within a building’s external envelope.

Augmentation of physico-mechanical, thermal and biodegradability performances of bio-precipitated material reinforced in Eucheuma cottonii biopolymer films

Green reinforcement in biopolymer for enhanced industrial application is on the increase. Bio-precipitated CaCO3 was synthesised via the process of microbially-induced calcium carbonate precipitation using Bacillus sp. strain. The bio-precipitated CaCO3 (B-PCC) and conventional CaCO3 precipitates (C-PCC) reinforcement effect on the properties of Eucheuma cottonii film was analysed and compared. The biocomposite films were fabricated using a solvent casting technique. The physicomechanical, thermal and biodegradability performances of B-PCC and C-PCC incorporated E. cottonii film with increasing fillers' contents [0.05, 0.10, 0.50, 1.00, 2.00 (wt.%)] were determined and compared through a range of testing include water vapour permeability (WVP), contact angle using sessile drop method, scanning electron microscopy (SEM), tensile, elongation, Young's modulus, thermogravimetric analysis (TGA), and soil burial test. A further comparison was made between the E. cottonii biocomposite film with the existing biodegradable mulch films to evaluate its potential application using wet cup method. Results revealed that biocomposite films embedded with 0.1% B-PCC appeared to exhibit higher water barriers and hydrophobicity behaviours than those embedded with C-PCC. However, the mechanical strength and thermal stability were slightly lower than those embedded with C-PCC. E. cottonii biocomposite films, especially those embedded with 0.1 wt. % B-PCC has shown the potential in agricultural mulch film as it promoted better biodegradation and tensile strength by 34.24% and 20% respectively compared to the existing biodegradable PLA/PBAT mulch film, making it a promising alternative to the conventional plastic to mitigate plastic pollution.

Sap Beetles (Coleoptera: Nitidulidae) in Oak Forests of Two Northeastern States: A Comparison of Trapping Methods and Monitoring for Phoretic Fungi.

Oak wilt is slowly expanding in the northeastern United States. Several nitidulid beetle species are known vectors of the fungus [Bretziella fagacearum (Bretz) Z. W. De Beer, Marinc., T. A. Duong, and M. J. Wingf (Microascales: Ceratocystidaceae)] that causes this disease, acquiring spores from fungal mats on infected trees and transmitting them to uninfected trees. Survey and fungal isolation from captured nitidulid beetles could be an important tool for detecting the presence of this disease in a geographic area not previously known to have oak wilt. In preparation for monitoring activities in such areas, two trapping studies were conducted in the northeastern United States: 1) trap test comparing the efficacy of wind-oriented pipe, multiple-funnel, and modified pitfall traps for nitidulids and 2) wet and dry collection cup comparison. Lures were a combination of nitidulid pheromones and fermenting liquid. Results support the use of multiple-funnel traps over the other two trap types, for both targeted species-specific surveys and community sampling. More total nitidulids, Colopterus truncatus (Randall), and Glischrochilus fasciatus (Olivier) were captured in wet collection cups compared with dry cups. Twenty-seven fungal species were isolated, none of which were B. fagacearum. Many fungi isolated from beetles were plant pathogens, indicating that in addition to the oak wilt fungus, sap beetles may contribute to the spread of other plant diseases.

Experimental investigation and performance evaluation of a mixed-flow air to air membrane enthalpy exchanger with different configurations

This paper presents an experimental investigation and performance evaluation of a mixed-flow air to air membrane enthalpy exchanger with different flow configurations. The moisture diffusivity, water contact angle and elastic modulus of five porous membranes were first experimentally determined using a wet cup test method, a contact angle meter and the tensile test, respectively. The five porous membranes investigated consisted of two Polyvinylidene difluoride membranes with the mean pore diameters of 0.22 µm (PVDF22) and 0.45 µm (PVDF45) respectively, two Nylon membranes with 0.1 µm and 0.45 µm pore sizes respectively and one Polyethersulfone (PES) membrane with a 0.1 µm pore size. The optimal membrane was then identified and used to fabricate an enthalpy exchanger. Lastly, the performance of the enthalpy exchanger with different mixed-flow configurations was experimentally investigated. The results showed that the PVDF45 membrane offered the highest moisture diffusivity (1.91 × 10−6 ± 2.42 × 10−8 m2/s) with hydrophilic surface and a relatively high elastic modulus (4.97 × 108 ± 3.86 × 107 Pa). It was shown that the enthalpy exchanger with Z-shape flow of the supply air stream and И-shape flow of the exhaust air stream at an entrance ratio of 0.25 offered the best thermal performance as the sensible, latent and total effectiveness increased by 12.3%, 15.1% and 14.6% respectively, when the flow rate was 0.3 l/s, as compared to that of the pure cross flow. The same flow configuration was able to recover the highest energy among all configurations investigated.

Generative reverse-modelling approach to hygrothermal material characterization

Reliable hygrothermal modelling depends on the quality of material characterization, especially so when higher moisture contents are concerned. Previous research has shown that adding additional material tests (e.g. capillary condensation redistribution (CCR) test) to the experimental dataset brings improvements to the modelling accuracy, but also adds to the workload of characterization process. This paper discusses a generative optimization workflow to increase the speed of the characterization and quality of the result. The proposed workflow incorporates optimization tool GenOpt and hygrothermal modelling software IBK Delphin to search for best fit of the water vapour and liquid conductivity curves of interior insulation materials based on modelling the CCR, drying and wet cup tests. Finally, models using material data from the proposed workflow and from the software database are compared to measurement results from two studies on interior thermal insulation. The results suggest that the generative optimization shows promise on the grounds of reducing tedious work analysing material tests. Also, a wider experimental dataset is shown to be useful when characterizing the vapour and liquid conductivity functions in over-hygroscopic region.

Experimental Comparison of Construction Material Vapor Permeability in Case of Horizontal or Vertical Sample Position

The paper proposes a device for vapor permeability coefficient determination in case of vertical sample position. The device is a L-type section capacity with a window in upper part of long side of the capacity. A test sample of construction material is positioned vertically and sealed in the window. The capacity has built-in relative air humidity sensors distributed along capacity height. These sensors allow measuring height-average relative air humidity. Experimental vapor permeability coefficient values, obtained by means of the proposed device and by means of well-known wet cup method, have been compared. Rock wool has been used as a test material. As a result, wet cup method has been confirmed for vapor permeability coefficient determination for vertical enclosing structures.

Experimental and numerical analysis of moisture transport in walnut and cherry wood in radial and tangential material directions

The diffusion properties of walnut (Juglans regia L.) and cherry (Prunus avium L.) wood perpendicular to the grain are presented. The wet and dry cup tests were carried out in normal climate conditions. Simultaneously, inverse analyses by means of the finite element (FE) method were conducted based on the experimental sorption data. The results show that the numerically derived diffusion model can predict the mass changes during the experiments with sufficient accuracy with a maximum global relative error of 0.43%. However, the numerically determined diffusion coefficients do not show an agreement with the experimental data.

Moisture uptake and permeability of canvas paintings and their components

Abstract Canvas paintings may show significant dimensional changes and experience internal stresses with fluctuating relative humidity. The relatively high and rapid absorption and drying of moisture within the different layers makes them more vulnerable than panel or wall paintings in comparable conditions. The dynamics of the moisture response is controlled by the water vapour permeability of the different layers. This paper presents a quantitative investigation of the vapour sorption and permeability of a selection of canvas painting components and of reconstructed paintings made of them. The selection of test samples was based on a survey of the materials used by Cuno Amiet in his early work and encompasses linen canvas, collagen glue sizing, chalk-glue ground and brown umber pigmented oil paint. Dynamic Vapour Sorption (DVS) tests were performed to obtain sorption isotherms. The vapour permeability was analysed in terms of the vapour resistance of layers and measured by means of wet cup and dry cup tests as well as in double chamber tests. The principle of incremental resistances was used to discriminate between the properties of the different layers. Whereas glue and canvas are comparable in being strongly absorbent, it appears that their vapour resistance is very different: a continuous glue film has a much higher vapour resistance than a canvas. In this context, we found that the method of applying glue sizing on a canvas influences the permeability of the resulting sized canvas: a gel size forms a more continuous glue film and hence leads to higher vapour resistance of the system, as opposed to a liquid size. Chalk-glue grounds have low moisture sorption, when compared to the high absorption of the proteinaceous glue, because they consist largely of chalk particles, which are not hygroscopic. The umber oil paint stands out for its low sorption and its high resistance to vapour transfer. These results characterise the highly heterogeneous nature of the multi-layered system of a painting in a quantitative way, enabling to better interpret damage phenomena and to make computational predictions of the influence of changing boundary conditions.

Heat and Water Vapor Transport Properties of Sandwich Composite with Aerogel Insulation

Several thermal insulation systems were developed for improvement of thermal performance of buildings. Exterior thermal insulation systems represent usually natural solution of the problem of low thermal resistance of building envelopes. However, in some cases, there is necessary to realize interior thermal insulation systems, what brings number of possible problems. Their common disadvantage is a limitation of interior space due to the thickness of thermal insulation layer and a possible condensation of water vapor which permeates the thermal insulation system. On this account, new sandwich composite with silica aerogel originally designed for application in interior thermal insulation systems is studied in the paper. Thermal properties are measured by two transient methods using devices ISOMET 2114 and RTB. The water vapor transport parameters are determined on the basis of dry cup and wet cup methods. The obtained data gives information on thermal and water vapor transport properties of the particular layers of sandwich composite and predetermines its behavior at real climatic exposure of building.

Design Factors That Influence the Performance of Flight Intercept Traps for the Capture of Longhorned Beetles (Coleoptera: Cerambycidae) from the Subfamilies Lamiinae and Cerambycinae

In North America, cerambycid beetles can have significant ecological and economic effects on forest ecosystems, and the rate of introduction and/or detection of exotic species is increasing. Detection and survey programs rely on semiochemical-baited intercept traps which are often ineffective for large woodborers like cerambycid beetles. This study examined the effects of flight intercept trap design on the capture of cerambycid beetles in the subfamilies Lamiinae and Cerambycinae. These subfamilies are the two largest in the Cerambycidae and they include many of the most damaging cerambycid pests and species on regulatory watch lists in North America. This study demonstrates that intercept trap design, treatment of trap surfaces with a lubricant, and the type of collection cup all influence the capture of beetles from the subfamilies Lamiinae and Cerambycinae. It also demonstrates that the addition of a large lubricant-treated collar to the bottom funnel of a multiple-funnel trap significantly increases the capture of some Lamiinae. The best trap design for both subfamilies was a lubricant treated multiple-funnel [MF] trap equipped with a wet cup and lubricant treated large collar on the bottom funnel. This design captured between 4 and 14 times more Lamiinae and Cerambycinae than commercially-available MF and panel traps.